


Patience Both Thin And Thick

by lupinjoallen



Category: Sherlock (TV)
Genre: Fantasy AU, M/M, Merman!Reader, Shameless Smut
Language: English
Status: Completed
Published: 2018-10-12
Updated: 2018-10-12
Packaged: 2019-07-30 01:05:38
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 1
Words: 1,806
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16276016
Author URL: https://archiveofourown.org/users/lupinjoallen/pseuds/lupinjoallen
Summary: Y/N is a mermaid and Sherlock is a fallen angel that have both been friends for a long time. But it's mating season for Y/N's kind and he has no boyfriend.





	Patience Both Thin And Thick

To Sherlock, magic was simply another science under his belt. He dabbled in alchemy, of course, more so than others, but learning about the Elven magics was of interest to him. However, he wasn’t just sure how interested he was until he discovered Y/N’s secret.

Y/N was a Ranalir, an elf of the ocean. He only discovered it by accident. He broke into Y/N’s flat, expecting to find him passed out in his bed. Instead, he was dozing off in his tub, his tail languidly swaying over the edge of it. Sherlock approached, realizing Y/N was soaking himself in salt water. Rightfully so, as pollution had been detrimental to Ranalir health in the recent past. Sherlock had carefully traced his fingers over his scales, startling Y/N awake. He could see the blush through the fogged water.

Since then, Sherlock had learned much more about Y/N until he noticed something about Y/N’s body. It seemed flushed and he was anxious. He waited until John was out to confront him.

“Is something wrong?” He asked gently. Y/N cheeks flushed red as he tried to focus on his book. “It’s something you find embarrassing. Odd. You’re rarely humiliated by the questions I ask you, so this must be something of an exception.” Y/N bit his lip, contemplating. “You’re wanting to tell me but you think I’ll think little of you--”

“It’s mating season.” Sherlock blinked at that. “My body is...needing attention from a potential mate and...yeah.”

Sherlock stared at him curiously before asking, “Will you have to go back?”

“What?”

“Go back to your village, I mean. Or does it not have to be exclusively a Ranalir?”

“No, just...in general someone,” Y/N mumbled, blushing more now. Sherlock approached and marked his spot in the book. “What are you doing?”

“You’re in pain right now because you need someone. I’d like to volunteer.” Y/N went red at that. “I’ll admit, I’m curious about how the process works.”

“So...just experimenting?” Y/N asked. Sherlock nodded. Y/N gulped. “Sherlock, I can’t. You don’t understand--”

“Then explain.”

“We mate for life.” Sherlock stared at him. “If I...we do that, then I can’t have anyone else. It’s you and me and no one else.”

“Is that entirely bad?” Sherlock asked simply as he sat beside him, placing the book on the coffee table. “We’ve never been interested in anyone else intimately. You often make jokes about women you find attractive, but in reality, you’ve never made a move on anyone. If it bothers you that much, I can simply swing by a shop and get you a toy--” Y/N laughed a bit at that. “What?”

“Just the thought of Sherlock Holmes going into a sex shop. You’d be completely blank faced as you grab probably the worst thing.”

“What could be so horrible?”

“You’d get a dildo that’d be way too big to humanly fit in any hole,” Y/N kept giggling. Sherlock smiled as Y/N calmed, thinking about it. “Sherlock, I don’t know. Even being friends...this is big for us both.”

Sherlock shrugged. “I’d rather it be someone I can trust more than anyone else.”

“Why not John?” Y/N teased.

Sherlock rolled his eyes. “Cuz he’s an idiot.” Y/N relaxed and leaned against him. “Would you really want to try?”

Y/N thought about it for a moment before nodding. “I trust you more than anyone else,” He admitted. “I’m just...I’m a bit scared.”

“Because you’re transgendered?” Sherlock asked. He shrugged. “Never bothered me. Surprised me as I know your kind are very traditional. But you’ve always been a black sheep.” Y/N smiled, nuzzling his shoulder. “Overly affectionate. You’re aroused. I haven’t even done anything.”

“You’re an ass,” Y/N laughed before looking up at him.

They both hesitated for a moment, watching one another before Sherlock leaned in. His lips brushed against Y/N’s, a soft breath escaping the elf. He shyly closed the gap, kissing Sherlock gently. The kiss was slow and intimate, surprising Sherlock. He accounted this for Y/N’s DNA, a need for a single mate in life. He himself gently kissed, only knowing what he’d read and seen in others.

He cupped Y/N’s face and shyly deepened the kiss. Y/N smiled a bit, making Sherlock smile. “Is that normal?”

“Smiling? I’d assume so. Adrenaline could be it too,” Y/N amended.

Sherlock hummed, trailing his hand down the elf’s neck. He felt his pulse and smiled. “Heart rate increased, pupils expanded...I think you’re right. The arousal doesn’t help though.”

“Quit deducing. Just fuck me, Sherlock,” Y/N whined before pouncing at the detective. Sherlock grunted then gasped as Y/N’s hands clutched at his back. Y/N blushed a bit before smiling. “I always forget.”

“Even though you helped me heal?” Sherlock teased. He pressed his back against Y/N’s hands. He kissed his nose. “You’re the only one who still looks to me as though I’m an angel.”

“Wings or no, Sherlock, you are an angel,” He said as he climbed into his lap.

Sherlock smirked and kissed him again as he lifted him. “Bedroom would be much larger than the couch.”

Y/N smiled and kissed his neck affectionately as he carried him. Sherlock laid him down carefully before standing. He shed away his shirts as Y/N stripped completely. Sherlock licked his lips nervously. “I…”

“Want me in control?” He asked, watching the detective. Sherlock nodded and Y/N guided him to lay in the bed. Y/N shyly traced his hands over Sherlock’s chest and stomach, learning the sensitivities of his skin. “Sherlock--”

“If you ask me one more time if I’m sure, I will pounce at you,” Sherlock said simply.

Y/N smirked a bit. “So impatient. Always eager to get to the good stuff.”

Sherlock groaned and sat up, kissing him as he reached between Y/N’s legs. He carefully teased his folds, making the merman shiver and whimper softly against his mouth. Sherlock hummed, feeling how wet he was before sliding a finger in. “You’re too patient,” He muttered.

Y/N whined and moaned as Sherlock fingered him open, sliding in a second finger not long after the first. Finally, Y/N swatted his hand away and tugged desperately at Sherlock’s trousers. Once Sherlock finally had his cock out, he eagerly pulled Y/N on top of him. Slowly, the merman sunk onto him.

“Oh gods,” Y/N moaned, shaking as Sherlock stretched him open. He whimpered and moaned, clinging to him. Sherlock could only pant as he watched Y/N adjusting to him. He felt more than saw the bond snapping in place between the two of them as Y/N met his eyes.

Sherlock moaned as Y/N began to ride him. He gripped Y/N’s hips, helping him along his length as he moaned softly. Y/N’s nails dug into his chest and his clit rubbed against his underwear as Sherlock hadn’t been able to strip completely before Y/N pounced at him. He watched the way his cock disappeared between Y/N’s legs, swallowed by his cunt.

“Fuck, Y/N,” He moaned, gripping at his butt. The merman gasped in pleasure and rocked harder, making them both moan louder before Sherlock moved him under his body. Y/N looked up at Sherlock with surprise and lust. “I need to make sure you feel better,” He growled softly before thrusting hard into him.

Y/N moaned louder, back arching off the bed. His heat began to subside, only to be replaced by the overwhelming pleasure. He moaned and writhed, desperate for a release. Sherlock angled his hips and quickly found Y/N’s sweetspot. Y/N moaned out his name and Sherlock groaned louder at the sound before pinning his legs to his chest.

“Oh, Sherlock!” He moaned louder, surprised by how much deeper Sherlock was going.

Sherlock watched him, looking down and seeing the way Y/N’s stomach buldged as he pushed deeper. “Look at that. I’m so deep inside you, Y/N,” He moaned, smirking a bit. “I bet I could breed you like this if you wanted to have children.” Y/N blushed, flustered by the notion. “You like that? The thought of being fucked full of my children?”

“Yes,” Y/N moaned, shaking. “Fuck, Sherlock. I...please! Please, I wanna cum so badly!”

“Cum then. I won’t stop you. I plan on making you feel good, so let me watch you orgasm on my cock.”

Y/N shook and moaned, pushing his legs free of Sherlock’s grasp and wrapping them around his waist. He gripped Sherlock’s hand as his face twisted and his walls clamped down around Sherlock. The detective moaned as he felt Y/N’s juices soak him, leaking down and wetting his clothes. Sherlock gripped his hips and thrust faster into him, chasing his own orgasm before finally releasing.

The merman gasped and moaned, feeling the cum pumping into him. He then pulled Sherlock down, kissing him as they rode through the pleasure. Soft sighs and whimpers escaped them both as they fell from the high.

Finally, Y/N practically collapsed limply under Sherlock, panting desperately. Sherlock grunted as he pulled away, watching the cum sliding out of Y/N’s abused hole. He hummed and adjusted.

Y/N gasped when Sherlock’s tongue slid against his folds, sensitive now. “Sh-Sherlock! Oh!” He moaned, thighs already shaking again as Sherlock’s tongue lapped everything up, leaving him helpless to the assault. He listened and felt Sherlock moaning against him as he tasted his everything. Sherlock’s hands held Y/N’s thighs apart, not that he’d have the strength to clamp them down around Sherlock.

Sherlock carefully moved his mouth, sucking Y/N’s clit between his lips as he slid two fingers into him. The stimulation was too much and Y/N shouted his pleasure as he orgasmed again, shaking terribly. Sherlock only moaned and worked him through it before pulling away. He sucked his fingers clean as he watched Y/N meet his gaze.

“I may have a new addiction,” He admitted before kissing Y/N. “Never knew sex would feel that good.”

Y/N whimpered as he tasted himself on Sherlock’s lips. The detective’s hands rubbed up his sides lazily and he couldn’t help the whine that escaped. “You’re horrible,” He mumbled weakly.

“Yet you’re the one who is desperate for me,” Sherlock teased, earning a playful nip. He chuckled and kissed Y/N’s head. “We should rest for now. I doubt you’ll have long before your heat acts up again.”

“Don’t say it like that,” Y/N whined. “It makes me sound like an animal.” Sherlock smirked. “Shut up.”

Sherlock just kissed Y/N fondly, holding him close.


End file.
